The Pluto Revolt: Leading Astronomers Want the Plutoid to be Reinstated as a Planet
Written by Ian O'Neill
If you thought Pluto was going quietly and giving up its planetary status without a fight, think again. Leading astronomers have spoken out against the International Astronomical Union (IAU) decision to classify the dwarf planet as a "Plutoid," described by some critics as a "celestial underclass." The IAU decision was made after it was deemed that Pluto cannot be called a "planet." Although the spherical rocky body can tick most attributes of being a "planet," the IAU pointed out that Pluto is too small to be capable of gravitationally clearing its own orbit (plus it periodically crosses the path of Neptune's orbit); it should therefore be called a "dwarf planet." Back in June however, the IAU gloriously announced that Pluto should be now be re-classified as a "Plutoid" and any other Pluto-like planets should follow suit. But on Thursday, at a major conference in Maryland, leading astronomers will refute the Plutoid classification saying the IAU re-naming is confusing and unworkable…
It may be
- It is in orbit around the Sun.
- It has sufficient mass so that it assumes a hydrostatic equilibrium (nearly round) shape.
- It has "cleared the neighbourhood" around its orbit.
Pluto fulfils #1 and #2, but fails on #3, it is simply too small to gravitationally clear its own orbit. So Pluto was caught right in the middle of the "planetary classification debate '06" and incidentally failed on one count. If any object fulfils the first two planetary criteria, but fails on the last, the IAU would classify the celestial body as a "dwarf planet." To complicate matters, Pluto also travels inside the orbit of the gas giant Neptune periodically, giving it the extra classification of being a Trans-Neptunian Object (TNO). Although Pluto is a "dwarf" by Solar System standards, it is one of the largest Kuiper Belt Objects (KBO) in the outer Solar System; a true King amongst dwarfs.
Pluto has had a hard few months after getting kicked out of the planetary club.
So, for two years, Pluto was stuck in no-man's land. It had been re-classified as a dwarf planet and astronomy teachers had to re-write their teaching material. Websites like NinePlanets.org had to scrub the 9 and replace it with an 8; but also had the foresight to buy "EightPlanets.org." Times were a little messy for Pluto. Then, in June this year, the IAU seemed to want Pluto to feel a little better. Not only was it the King of the Kuiper Belt, it would have an entire army of Pluto-like dwarf planets named after it. The IAU created the "Plutoid," and as if to avoid any more confusion, it gave the classification a no-nonsense definition:
Plutoids are celestial bodies in orbit around the Sun at a semi major axis greater than that of Neptune that have sufficient mass for their self-gravity to overcome rigid body forces so that they assume a hydrostatic equilibrium (near-spherical) shape, and that have not cleared the neighbourhood around their orbit. Satellites of plutoids are not plutoids themselves. - The IAU definition of a Plutoid (June 11th 2008).
Got that? Good. But not everyone was happy, least of all Pluto. T-shirts have even been printed with the quote: "It's okay Pluto, I'm not a planet either" (and yes, I have one), for anyone wanting to show their support for the struggling rocky body.
So this Thursday, some very prominent astronomers will take their case to the "The Great Planet Debate: Science as Process" conference at The Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. To cut a long story short, they want Pluto to be reinstated as a planet, thereby abandoning the term "Plutoid."
Dr David Morrison, director of the NASA Lunar Science Institute in California, makes the point that if the largest planets in our Solar System can be called Gas "Giants" then it should be fine to call Pluto a "Dwarf" Planet. But in the current IAU classification, Pluto cannot be called a planet.
"It has never before been necessary for any organisation to define a word that has been in common every day use so I see no reason why it was necessary on this occasion. Astronomers use adjectives such as giant and dwarf to describe different subclasses of objects like planets, stars and galaxies, so why could Pluto not remain as a dwarf planet just as Jupiter is a giant planet. Also, around 90 per cent of the planets we know now are outside our solar system, but under the International Astronomical Union’s definition, they cannot be classed as planets." - Dr David Morrison
So it would seem the classification of "planet" will remain a very exclusive club of eight under the IAU rules; only Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune will have this honour unless the scientists at the Great Planet Debate conference can convince the IAU otherwise. Mark Sykes, from the Planetary Science Institute, argues that only #2 of the IAU planet definition need be applied; it is therefore the shape, or roundness, of the object that defines whether it can be called a planet or not. If this definition were applied, the Solar System would expand to include 12 planets. This worries some traditional thinkers at the IAU. As our observational techniques improve, more planet candidates will be discovered, therefore making the Solar System wildly different than what it is now.
But if there are more "planets" out there, why shouldn't more planets be added to the official eight we currently have? It sounds like the Pluto debate is far from over and it will be interesting to hear what the delegates have to say on Thursday…
Source: Telegraph
Filed under: Pluto
August 11th, 2008 at 4:51 pm
In a rare display of primal screaming, 12 angry scientists took to the lower frequency airwaves defending Pluto. They refused to acknowledge anything other than a planet named Pluto and said the "Plutoid word was nothing more than excrement from pitiable, wanna-be researchers who don't know a freaking thing about the universe. We fart in your general direction and shall never tire of taunting you." Next time: conspiracy theorists link the plutoid debate with black helicopters and Project Lucifer…stay tuned.
August 11th, 2008 at 6:39 pm
The article is clearly biased. Where are the "leading astronomers"? Who are the "very prominent astronomers"? The only name you could dig up was Mark Sykes who opposes reclassifying Pluto a plutoid.
This is no news article. It is simply a rehashing of old whiners who can't let go of their baby blankets.
Classifying and reclassifying and subclassifying not only planets but ALL objects found and studied in science is a normal and essential process if science is to progress and advance.
If you can't seem to handle that fact because of abnormal psychological reasons, then perhaps science isn't your bag.
Try a subject where everything always stays the same like…..NOTHING.
August 11th, 2008 at 6:45 pm
Ion O Neil, try coming up with a real news story. The information that someone is selling Pluto t-shirts so they have something to dry their eyes on doesn't cut it as news bud.
August 11th, 2008 at 8:55 pm
Pluto is a Kuiper Belt Object. Period.
It must be a REALLY slow day on the global warming, (AHEM!) climate change front.
I personally like the story. 'Ian' (get it right, where did you go to school anyway, California?) and the rest of the UT staff do a great job of getting us excellent articles on astronomy.
August 11th, 2008 at 10:04 pm
Pluto is a Kuiper Belt Object AND a planet–as are Eris, MakeMake, and Sedna. There is no reason that objects in the Kuiper Belt that are in a state of hydrostatic equilibrium cannot simultaneously belong to both categories. These objects are unlike the other KBOs because objects in hydrostatic equilibrium have geophysical processes unlike inert asteroids, which do not.
Yes, classifying, reclassifying, and subclassifying objects in science is a normal and essential process–IF that reclassifying, etc. is based on sound reasoning and makes actual sense. The IAU reclassification does not do either. Resorting to derogatory personal attacks against those who, for solid logical reasons, reject the IAU decision, is nothing more than an ad hominem attack and does nothing to promote your position.
August 11th, 2008 at 11:26 pm
Scientist are to occupied by the need to categorize everything. I refer to this as BSology and I'd like to write a book about it if I live long enough. This is an ongoing problem in other branches of science. As man discovers something new he realizes that his existing categories are insufficient to define all of the discoveries. Then we have a big meeting and invite all the world members of our professional organization that we joined to feel self important. By a vote of members, we exercise our power over everything that you know. We create a new class, order or whatever. Because we said it, it is so. Change the books because we have voted. Redefine right and wrong because we have voted and our vote makes you wrong.
I still support the notion that only one thing qualifies what is a planet. “2. It has sufficient mass so that it assumes a hydrostatic equilibrium (nearly round) shape“. Moon and Titan and many others are planets.
August 12th, 2008 at 12:13 am
Wouldn’t that make every other American a planet, except in Beverly hill of course.
August 12th, 2008 at 3:29 am
How can we gauge what is and what isn't a planet by it's size - how lumpy it is - what it's made of - if it keeps its pathways clean or not - or what? That stuff is simply fudge because there are no clearly defined boundaries. The questions will remain as to how much is enough or not enough. (Maybe that's what Science wants).
On the other hand, if we can locate Pluto as existing within a Bode's Law orbital zone, mainly beyond and therefore larger than Neptune's, and are sure that it is the largest body in that zone, I feel that it has the right to be a planet - because
The largest body should be the dominant collector of dust and rocks etc. in that zone. That being so, as it collects, it will grow and that means that eventually it could qualify as a planet under to-days thoughtless, shortsighted, meaningless criteria.
David
August 12th, 2008 at 3:46 am
So what if more planets are discovered thus making the Solar System radically different to the way it appears now? I don't recall a fuss being made when Uranus and Neptune were discovered and disturbed the 'classical' view of the system. We're not at a special time when 8, and 8, only is THE number to have. What happens when we travel out there and find bodies similar in size to Mars or Mercury?? Let the Solar System have 9, 20, 100 planets. Future generations will howl with laughter at this debate. There are at least 12 planets - move on, next scientific discovery please.
Paul.
August 12th, 2008 at 8:39 am
Leave it at "Plutoid" and all others like it. It's honorable and appropriate.
August 12th, 2008 at 9:50 am
From a philosophical point of view.
A planet - is a planet, that - nobody can change.
In this respect I will say, things are what they looks like.
I enjoy to define things for my own sake, and believe it's a good things in order to keep a certain order in my head - and thereby understanding.
I prefer to view IAU's decision as a positiv thing - allthough I disagree with their decision - simply because it has created a debate … and coursed me to get a better definition on the 'planet' term.
My final decision in defining the term planet is: "A spheric object free in space".
"Free in space": If a spheric objekt is in permanent contact to another object - I will call it a ball.
"Spheric object": It has just come clear to me that a 'spherical object' is the very first visible sign of 'order' in the univers … of natures marvellous ability to create order in kaos.
And yes, if an electron/proton/neotron or any other subatomic particles is believed og known to be spherical they are also planets - atomical planets.
Consequently I view:
'Stars' as planets - lightplanets or 'Galaxy planets'.
The next in the order … please notice the allready used term of astronomers "extrasolar planets". For me I would call them starplanets or in our case - sunplanets. Subtitles could be as allready used "giant plantets" - "dwarfplanet", and other terms refering to their substance.
For planets not circling around a particular object, is for me "wild planets"
If an object clearly have obtained a spherical shape, but then by colision have lost this spherical shape, it is a "damaged planet".
Then Moons: "Moonplanets".
'None spherical' objects cirkling another object, is for me a satelite, regardless its size.
I realise that the basic foundation for my planet definition, is the ''spherical shape", whitch I consider no more or less than marvellous. And, in reallity sufficient for me, in the defining characteristic of a planet - provided it is 'free in space'.
In reallity, I do not care that much about what the IAU decide, as long as it works for them as a working model - or means of communication. Yet, it disturbes me somehow, since it has such a greath impact to a whole lot of human comprehensions - including the world of writings - symbolism etc. Yet, I really would welcome this new way of defining our solar system, if it made som sense to me - but it doesn't, it seems only to add confusion in our common comprehension of our solarsystem, not to mention our definition of universal objects.
Also - remember: It only takes an idiot to confuse and complicate - about anything. But a genious, to make complicated things clear and understandable.
In general, I beleive that in the mass of astronomers, there are a whole bunch of genious people - do I or we have hope for a better and revised definition of the term planet?
Harry
August 12th, 2008 at 12:01 pm
To get a good idea at how to compromise over this one should look at how the continent and islands are defined on Earth. I think we can all agree that the continents are North America, South America, Europe, Asia, Africa, Australia, and Antarctica. But how are they defined? We could come up with a three point system: (1) on their own continental plate, (2) have a culturally distinct population, (3) surrounded by oceans on all sides. However Europe would fail since its not surrounded by water and (arguably) not on its own plate (Europe collided with Asia 270 million years ago and the two former plates fused into one Eurasian plate - no new mountain building in the Urals). If we dropped the water requirement (3) then we'd have to promote India from a sub-continent to a continent since certainly on its own plate (the Himalayas are still growing!) and has a culturally distinct population. If we drop the plate requirement (1) then Greenland, Madagascar, and New Guinea could argue for continental status. We could define a continent by size using a nice round base 10 number - i.e. over 10 million sq.km - but then Australia gets demoted to an island of 7.6 million sq.km.
The continents were named in antiquity as really big chunks of land defined by natural barriers (oceans and/or mountains) with culturally distinct populations resulting in an exclusive club regardless of the advancement of scientific knowledge.
Maybe its time to say "yup" and define Pluto (Europe) as a planet (continent) because this is an exclusive club defined by history. Then Ceres (India) is dwarf planet/big asteroid (sub-continent) again for traditional reasons. And finally Sedna, Eris, (et al.) out in the Kupier Belt and the asteroids in the Asteroid Belt (Greenland, Madagascar, New Guinea, New Zealand, Newfoundland and Britain) are KBOs/Plutoids or asteroids (islands).
August 13th, 2008 at 2:50 am
Ah, yes, Watchful Stone Guardian - but does Pluto gain a semblence of respect if other objects are termed Plutoids in its honour? Perhaps they will all have to be smaller, or otherwise inferior in every way. And we who feel the shame in this debate can only pray that Pluto will some day clear its rocky domain and gather those detached particles to its bosom, and grow, and grow, and grow; and may the doubters and scorners and other nasty people, join that growing mass.
How sad and simply ironic
Our views are far from platonic
As milk becomes curds
The meaning of words
May well be described as Plutonic
David
August 13th, 2008 at 6:10 am
tl;dr
Seriously, this is not science. Astronomers should stop wasting their time on the issue as I guess most of them already did.
August 13th, 2008 at 5:21 pm
Can't the IAU think tank come up with something better to do with their time? These guys are an embarrassment.
August 14th, 2008 at 9:59 am
As I remember this contoversy. It wasn't that Pluto didn't meet the definition of a planet.
What I recall is the definition of a planet was changed to displace Pluto
Am I mistaken??
August 15th, 2008 at 12:59 am
Hello there Guys,, i think we should leave the guys in the IAU as in their ass.. Theres nothing we can do in what are their empressions about this 9th planet called pluto as in tradition.. They know more than we are about this. so, please lets try to be an audience. and as a human, we cant force ourselves to be believed, because only God knows about all things we can see..
So!!! As on your ass Morons
August 15th, 2008 at 1:08 am
Hello there Guys,, i think we should leave the guys in the IAU as in their ass.. Theres nothing we can do in what are their empressions about this 9th planet called pluto as in tradition.. They know more than we are about this. so, please lets try to be an audience. and as a human, we cant force ourselves to be believed, because only God knows about all things we can see..
So!!! As on your ass Morons
August 15th, 2008 at 1:21 am
Maybe it will help to put a little perspective on this. These KBOs were planetoids on their way to becoming larger planets when Neptune wandered out and spewed them about like balls on a billard table after the break. Neptune captured one of the larger ones which is its moon Triton, A big one named Ceres got pulled into the Asteroid belt. Pluto and the rest all had their orbits disturbed and their development stunted as a result of being thrown out of their orbits. Thus the term dwarf planet is wholly appropriate. This debate may come up again however when we find Mars size objects or bigger that Jupiter likely threw into much more distant chaotic orbits when it migrated towards to sun. Will they be called planets or Trans-Jovian Objects or both? Certainly such objects cant be classified as dwarfs. I probably just thwarted my own argument, but as you can see none if this is simple.
October 4th, 2008 at 5:21 am
Hooray for Pluto! The smallest planet in the solar system will be once again!